From: "Paul E. McKenney" paulmck@kernel.org
This commit renames the srcu_check_read_flavor_lite() function to srcu_check_read_flavor_force() and adds a read_flavor argument in order to support an srcu_read_lock_fast() variant that is to avoid array indexing in both the lock and unlock primitives.
Signed-off-by: Paul E. McKenney paulmck@kernel.org Cc: Alexei Starovoitov ast@kernel.org Cc: Andrii Nakryiko andrii@kernel.org Cc: Peter Zijlstra peterz@infradead.org Cc: Kent Overstreet kent.overstreet@linux.dev Cc: bpf@vger.kernel.org Signed-off-by: Boqun Feng boqun.feng@gmail.com --- include/linux/srcu.h | 2 +- include/linux/srcutiny.h | 2 +- include/linux/srcutree.h | 10 ++++++---- 3 files changed, 8 insertions(+), 6 deletions(-)
diff --git a/include/linux/srcu.h b/include/linux/srcu.h index f6f779b9d9ff..ca00b9af7c23 100644 --- a/include/linux/srcu.h +++ b/include/linux/srcu.h @@ -279,7 +279,7 @@ static inline int srcu_read_lock_lite(struct srcu_struct *ssp) __acquires(ssp) { int retval;
- srcu_check_read_flavor_lite(ssp); + srcu_check_read_flavor_force(ssp, SRCU_READ_FLAVOR_LITE); retval = __srcu_read_lock_lite(ssp); rcu_try_lock_acquire(&ssp->dep_map); return retval; diff --git a/include/linux/srcutiny.h b/include/linux/srcutiny.h index 1321da803274..b347bde1aac2 100644 --- a/include/linux/srcutiny.h +++ b/include/linux/srcutiny.h @@ -82,7 +82,7 @@ static inline void srcu_barrier(struct srcu_struct *ssp) }
#define srcu_check_read_flavor(ssp, read_flavor) do { } while (0) -#define srcu_check_read_flavor_lite(ssp) do { } while (0) +#define srcu_check_read_flavor_force(ssp, read_flavor) do { } while (0)
/* Defined here to avoid size increase for non-torture kernels. */ static inline void srcu_torture_stats_print(struct srcu_struct *ssp, diff --git a/include/linux/srcutree.h b/include/linux/srcutree.h index 6b7eba59f384..e29cc57eac81 100644 --- a/include/linux/srcutree.h +++ b/include/linux/srcutree.h @@ -251,16 +251,18 @@ static inline void __srcu_read_unlock_lite(struct srcu_struct *ssp, int idx)
void __srcu_check_read_flavor(struct srcu_struct *ssp, int read_flavor);
-// Record _lite() usage even for CONFIG_PROVE_RCU=n kernels. -static inline void srcu_check_read_flavor_lite(struct srcu_struct *ssp) +// Record reader usage even for CONFIG_PROVE_RCU=n kernels. This is +// needed only for flavors that require grace-period smp_mb() calls to be +// promoted to synchronize_rcu(). +static inline void srcu_check_read_flavor_force(struct srcu_struct *ssp, int read_flavor) { struct srcu_data *sdp = raw_cpu_ptr(ssp->sda);
- if (likely(READ_ONCE(sdp->srcu_reader_flavor) & SRCU_READ_FLAVOR_LITE)) + if (likely(READ_ONCE(sdp->srcu_reader_flavor) & read_flavor)) return;
// Note that the cmpxchg() in __srcu_check_read_flavor() is fully ordered. - __srcu_check_read_flavor(ssp, SRCU_READ_FLAVOR_LITE); + __srcu_check_read_flavor(ssp, read_flavor); }
// Record non-_lite() usage only for CONFIG_PROVE_RCU=y kernels.